Elizabeth McClintock, a sociologist from the University of Notre Dame, has examined the impact of physical attractiveness and age on the selection of a mate and the effects of gender and income on relationships, offering insights into the timing of Cupid's arrows.

In a new study, published in Biodemography and Social Biology, McClintock examines the sexual and romantic outcomes - number of partners, relationship status, and timing of sexual intercourse — of physical attractiveness in young adults. Her results reveal the gender differences in preferences, as well.

“Couple formation is often conceptualized as a competitive, two-sided matching process in which individuals implicitly trade their assets for those of a mate, trying to ï¬nd the most desirable partner and most rewarding relationship that they can get given their own assets,” McClintock says. “This market metaphor has primarily been applied to marriage markets and focused on the exchange of income or status for other desired resources such as physical attractiveness, but it is easily extended to explain partner selection in the young adult premarital dating market as well.”

McClintock asserts that it is not only status and financial resources being traded for attractiveness, but also control over the degree of commitment and progression of sexual activity.

McClintock's study finds that highly attractive women are more likely to seek exclusive relationships instead of purely sexual relationships. These women are less likely to have sexual intercourse within the first few weeks of meeting a partner. McClintock suggests this difference exists because more physically attractive women use their greater power in the partner market to control outcomes within their relationships.

Another key finding is that for women, the number of sexual partners decreases with increasing physical attractiveness. Men, on the other hand, tend to have more sexual partners with increasing physical attractiveness. Weight plays a par in the number of sexual partners a woman will have as well. Thinness is a dimension of physical attractiveness, so weight is consistent with the finding that more attractive women have fewer sexual partners.

In a related, unpublished study, McClintock tests and rejects the trophy wife stereotype — that women trade their beauty for men's status.

“Obviously, this happens sometimes,” she says, pointing to Donald Trump and Melania Knauss-Trump as an example.

“But prior research has suggested that it often occurs in everyday partner selection among ℠normal´ people “¦ noting that the woman´s beauty and the man´s status (education, income) are positively correlated, that is, they tend to increase and decrease together.”

Prior research into this area has missed two very important factors.

First, people with higher status are, on average, rated more physically attractive – perhaps because they are less likely to be overweight and more likely to afford braces and nice clothes and trips to the dermatologist, etc.,” she says.

“Secondly, the strongest force by far in partner selection is similarity – in education, race, religion and physical attractiveness.”

McClintock's research into these factors has revealed that there is not a general tendency for women to trade beauty for money. “Indeed, I find little evidence of exchange, but I find very strong evidence of matching,” she says. “With some exceptions, the vast majority of couples select partners who are similar to themselves in both status and in attractiveness.”